Doctors at the University of New Mexico have discovered that a noticeable amount of two chemicals is released by the brain when it senses pain (search). They say this knowledge could turn what has been a subjective problem for patients into an objective science in which pain is measurable.

"When there are no physical signs of pain, it's very hard for patients to get any sort of acceptance from doctors," said Paul Mullins, who directs studies of the phenomenon at the UMN MIND center. "We sort of stumbled on this new way of actually seeing pain."

Mullins and co-investigator Wilmer Sibbitt finished their first yearlong study of the phenomenon about a month ago at the MIND center, which stands for Mental Illness and Neuroscience Discovery.

"Pain is interesting because the reaction to it differs from person to person," Sibbitt said. "You can put an adverse stimulus on two different people, and one will say there's almost no pain, and the other will be in agony."

The doctors stumbled onto the phenomenon when a researcher's ear got pinched by a pair of headphones during a brain scan.

"When it was over she told us she was in a lot of pain, and it might invalidate the results, but we thought it was interesting and looked for changes in brain patterns," Mullins said.

The pain triggered a large release of glutamine (search) and glutamate (search), which help nerves send signals through the brain.

Sibbitt said scans of the two chemicals will help doctors study painful diseases more closely and could lead to better pain-fighting techniques. The method could also help pharmaceutical companies develop better drugs to treat pain and study how drugs, diet and exercise work to fight it, he said.

"There are a lot of avenues to explore," Mullins said. "Other people have been looking for something like this, but we're the first to actually find it. We want to continue working on it and studying chronic pain populations so we can understand what's going on and hopefully help those people more effectively."